Coupling devices of this main type are previously known for connecting sections of pipes or hoses. Many different types of such coupling devices are known. One type which is of particular interest in connection with the present invention is that in which at least one main part of the coupling is provided with a valve which automatically closes the fluid duct in the part in question when it is disconnected from the other part. This function prevents, in the disconnected state of the coupling, the fluid from flowing out. The coupling device according to the invention has particular advantages since it is arranged like this type of coupling, which is provided with a valve.
Furthermore, the coupling device according to the invention relates to the field of quick couplings, i.e. the connecting and disconnecting operation can be carried out very quickly by means of a simple manoeuvre. Quick couplings of this kind are of a more developed type of couplings, as compared with the more conventional type which includes screw elements for connection of the two parts. This is something which implies that the connection and disconnection operation takes a longer time, since the turning of the screw element takes a certain time.
A drawback which is related to quick couplings is that a relatively high force must be used during connection and locking of the coupling parts to each other.
This force can be very high if one of the coupling parts is provided with a valve of said type and if this valve is influenced by a certain pressure from the fluid, since the valve body must be displaced against the force of the pressure by forcing the coupling parts together.